Distribution of silica-exposed workers by province and industry in Vietnam.

To determine the number and distribution of exposures among workers exposed to silica dust in Vietnam, a cross-sectional study was conducted of the provincial Preventive Medicine Centers (PMCs) of 61 provinces, and data were collected from medical centers (MCs) of the Ministries of Construction, Industry, and Transportation. The PMC survey identified 112,956 exposed workers in 31 provinces. Ministry data identified 240,744 exposed workers. Quang Ninh province, with 50,000-70,000, had the highest concentration. These estimates provide a range of 40,000-350,000 exposed workers, supporting the development of a validated registry of silica-exposed workers, essential to the development of a program for silicosis prevention in Vietnam.

Pneumoconiosis among workers in a Vietnamese refractory brick facility.

BACKGROUND: Vietnam is a rapidly industrializing country with increasing needs for building materials, including refractory bricks. The manufacture of refractory bricks results in high levels of free silica, a recognized occupational hazard. METHODS: A cross-sectional survey was conducted among 158 employees using a respiratory symptom questionnaire and ILO classification of radiographs for pneumoconiosis. RESULTS: The prevalence of radiographic silicosis (ILO category 1/0 and greater) was 10% in all workers with evidence of a dose-response gradient. Pneumoconiosis prevalence increased from 0% in workers employed < 10 years at the plant to 18% for workers employed > 20 years (trend test P = 0.01 for each year increment after adjusting for gender and tobacco use). CONCLUSIONS: Workers in this plant demonstrate a consistent pattern of radiographic evidence of pneumoconiosis, which appears to be related to duration of work. Future studies should assess exposure control measures that are appropriate to countries undergoing rapid industrialization such as Vietnam.